Reduce risk of publishing posts with wrong date

.github/workflows/main.yml

@@ -42,10 +42,23 @@ jobs:
         with:
           path: public
 
+  pub_date:
+    name: Check publication date for placeholder
+    if: ${{ github.ref == 'refs/heads/master' }}
+
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
+
+      - run: rustup override set ${{ env.RUST_VERSION }}
+      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+
+      - run: cargo test -p front_matter -- --include-ignored date_is_set
+
   deploy:
     if: ${{ github.ref == 'refs/heads/master' }}
 
-    needs: build
+    needs: [pub_date, build]
 
     permissions:
       pages: write

README.md

@@ -33,10 +33,14 @@ You can store your main blog post in `content/<some-slug>/index.md`.
 Images go into the same directory: `content/<some-slug>/my_image.png`.
 Now you can reference that image with a simple relative path: `![alt text](my_image.png)`.
 
+A post's date of publication is embedded in the `path` key of the front matter.
+Unless the exact date is known in advance, keep the placeholder (`9999/12/31`) until the post is about to be published.
+Don't worry, there's a CI check to prevent a post with a placeholder date from being deployed.
+
 Here is an example of the front matter format:
 ```md
 +++
-path = "2015/03/15/some-slug"
+path = "9999/12/31/some-slug"
 title = "Title of the blog post"
 authors = ["Blog post author (or on behalf of which team)"]
 description = "(optional)"

front_matter/src/lib.rs

@@ -141,15 +141,7 @@ mod tests {
 
     #[test]
     fn front_matter_is_normalized() {
-        let repo_root = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("..");
-
-        let posts = fs::read_dir(repo_root.join("content"))
-            .unwrap()
-            .chain(fs::read_dir(repo_root.join("content/inside-rust")).unwrap())
-            .map(|p| p.unwrap().path())
-            .filter(|p| p.is_file() && p.file_name() != Some("_index.md".as_ref()));
-
-        for post in posts {
+        for post in all_posts() {
             let slug = post.file_stem().unwrap().to_str().unwrap();
 
             let inside_rust = post
@@ -212,4 +204,36 @@ The post {post} has abnormal front matter.
             };
         }
     }
+
+    /// This test is run by the merge queue check to make sure a blog post isn't
+    /// merged before its date of publication is set. The date of a blog post
+    /// is usually a placeholder (path = "9999/12/31/...") until shortly before
+    /// it's published.
+    #[test]
+    #[ignore]
+    fn date_is_set() {
+        for post in all_posts() {
+            let content = fs::read_to_string(&post).unwrap();
+            let (front_matter, _) = parse(&content).unwrap();
+
+            if front_matter.path.starts_with("9999/12/31") {
+                panic!(
+                    "\n\
+                    The post {slug} has a placeholder publication date.\n\
+                    If you're about to publish it, please set it to today.\n\
+                    ",
+                    slug = post.file_stem().unwrap().to_str().unwrap(),
+                );
+            }
+        }
+    }
+
+    fn all_posts() -> impl Iterator<Item = PathBuf> {
+        let repo_root = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("..");
+        fs::read_dir(repo_root.join("content"))
+            .unwrap()
+            .chain(fs::read_dir(repo_root.join("content/inside-rust")).unwrap())
+            .map(|p| p.unwrap().path())
+            .filter(|p| p.is_file() && p.file_name() != Some("_index.md".as_ref()))
+    }
 }